comment-fixes.php

<?php

class Joost_Comment_Fixes {
    public function __construct() {
        // Unhook comment cookies stuff from core.
        remove_action( 'set_comment_cookies', 'wp_set_comment_cookies' );

        add_action( 'wp_footer', [ $this, 'print_custom_comment_script' ] );
        add_filter( 'wp_get_current_commenter', [ $this, 'ignore_comment_cookies_serverside' ] );
        add_filter( 'comment_post_redirect', [ $this, 'comment_moderation_redirect' ], 10, 2 );
    }

    /**
     * Filter the comment moderation redirect, to prevent adding unneeded parameters.
     */
    public function comment_moderation_redirect( $location, $comment ) {
        
        // Check if the comment is held for moderation.
        if ( $comment->comment_approved == '0' ) {
            // Redirect to a custom "held for moderation" page.
           // return home_url( '/comment-moderation/' );
           return get_permalink( $comment->comment_post_ID );
        }

        return $location;
    }

    /**
     * To prevent this data from being cached, we don't want to show it server side.
     *
     * @param array $commenter Ignored.
     *
     * @return array With empty values for all three keys.
     */
    public function ignore_comment_cookies_serverside( $commenter ) {
        return [
            'comment_author'       => '',
            'comment_author_email' => '',
            'comment_author_url'   => '',
        ];
    }

    /**
     * Prints a script that sets cookies for comment form field values on comment submission, and reads them from a cookie if it's there.
     */
    public function print_custom_comment_script() {
        if ( ! is_singular() || ! comments_open() ) {
            return;
        }

        ?>
            <script>
                // Function to set comment cookies.
                function setCommentCookies( name, email, url ) {
                    const oneYear = 365 * 24 * 60 * 60 * 1000;
                    const expiryDate = new Date( Date.now() + oneYear ).toUTCString();

                    // Set cookies for comment author data.
                    document.cookie = `comment_author=${encodeURIComponent(name)}; expires=${expiryDate}; path=/`;
                    document.cookie = `comment_author_email=${encodeURIComponent(email)}; expires=${expiryDate}; path=/`;
                    document.cookie = `comment_author_url=${encodeURIComponent(url)}; expires=${expiryDate}; path=/`;
                }

                // Function to read cookies.
                function getCommentCookies() {
                    const cookies = document.cookie.split( '; ' ).reduce(( acc, cookie ) => {
                        const [key, value] = cookie.split( '=' );
                        acc[key]           = decodeURIComponent(value);

                        return acc;
                    }, {} );

                    return {
                        name:  cookies['comment_author'] || '',
                        email: cookies['comment_author_email'] || '',
                        url:   cookies['comment_author_url'] || ''
                    }
                }

                document.addEventListener( 'DOMContentLoaded', function () {
                    // Populate comment form fields with cookie data.
                    const cookies    = getCommentCookies();
                    const nameField  = document.getElementById( 'author' );
                    const emailField = document.getElementById( 'email' );
                    const urlField   = document.getElementById( 'url' );

                    if (nameField)  nameField.value  = cookies.name;
                    if (emailField) emailField.value = cookies.email;
                    if (urlField)   urlField.value   = cookies.url;

                    // Set cookies on form submission.
                    const commentForm = document.getElementById( 'commentform' );
                    if ( commentForm ) {
                        commentForm.addEventListener( 'submit', function() {
                            if ( nameField && emailField && urlField ) {
                                setCommentCookies( nameField.value, emailField.value, urlField.value );
                            }
                        });
                    }
                })
            </script> 
        <?php
    }
}

new Joost_Comment_Fixes();